The aim of this chapter is to introduce the reader to the basic legal requirements for the safe use of ionizing radiation. This will cover the main documents involved in the UK and the basic organization of radiation safety in a hospital trust, and will then examine the practical ways in which these are implemented in radiology or radiotherapy departments.

Radiation dose rises from two sources: natural sources, which constitute the dose received by the whole population, and artificial sources. Radiation protection procedures can do little or nothing to reduce the dose from natural sources.

The principal component of radiation from artificial sources is received from exposure to radiation from medical sources. It follows from this that one of the basic tasks of radiation protection is to establish levels of risk to the population due from this source and then to take steps to keep these levels of risk from this source as low as possible.

The purpose of radiation protection in medicine is to produce and maintain an environment, both at work and in the outside world, where the levels of ionizing radiation from this source pose a minimal acceptable risk for human beings. Before beginning any discussion on radiation protection, it is important to realise that our environment can only be described as relatively safe from the effects of radiation from artificial sources.

Once the levels of risk from such radiation have been determined, appropriate dose-equivalent limits (see Sect. 44.6) may be set so that the risk associated with such radiations is no greater (and frequently is much less) than other aspects of life, e.g. the risk of injury as a result of a traffic accident. Establishing such dose-equivalent limits, and ensuring that staff work within these limits, helps to prevent suffering.

A full study of radiation protection would need to cover:

Such a vast scope of study cannot be covered in a single chapter, or even in one book. Only a simplified review of practical methods of reducing radiation doses to radiation workers and their patients from the medical use of ionizing radiation will be considered here. These points are covered in the core of knowledge which all radiographic staff are expected to learn as part of their education. This consists of 11 key items as summarized in Table 44.1. Items 1–9 are of particular importance to the operator, while items 10 and 11 have particular reference to the role of the practitioner.

Table 44.1 Core of knowledge

The legislation governing radiation is often confusing to the student. The International Commission for Radiation Protection (ICRP) has produced recommendations on radiation protection. These recommendations do not have the force of law. Laws based on these recommendations are then produced by the nations of the world.

In the European Union (EU), this is attained through directives, and all member states in the EU are required to implement these directives. In the UK, the following acts and regulations are concerned with radiation safety:

The inspectorate of the Health and Safety Executive (HSE) is responsible for ensuring that employers and employees comply with the above regulations. IRR 1999 applies to all radiation work and radiation workers in both the private and public sectors of the nuclear industry and those who may be affected by such work activities. In contrast, IR (ME) R 2000 applies whenever humans are irradiated for diagnostic, therapeutic, research or other medical or dental purposes, and where in-vitro medical tests are conducted. These regulations apply to staff, students, patients and their friends and relatives who are acting as comforters or carers, and to volunteers in research projects and members of the public. The above are all legal documents, and are often difficult for the layman to understand. ‘User friendly’ methods of meeting the requirements of these laws have been published as the Approved Codes of Practice and Guidance Notes. These do not have the force of law, but in a prosecution the defendant must be able to prove that their method of work is as good as, or better than, that recommended in the code or guidance notes.

Table 44.2 summarizes the dose-equivalent limits specified by the Ionizing Radiation Regulations 1999.

Table 44.2 Dose-equivalent limits (in mSv) per calendar year specified by Ionizing Radiation Regulations 1999

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Mar 6, 2016 | Posted by admin in GENERAL RADIOLOGY | Comments Off on Practical radiation protection

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CATEGORY OF PERSON	DOSE TO WHOLE BODY	DOSE TO LENS OF THE EYE	DOSE TO SKIN AVERAGED OVER AN AREA OF 1 CM2	DOSE TO HANDS, FOREARMS, FEET AND ANKLES
Employee aged 18 or over	20	50	500	500
Trainees aged under 18	6	50	150	150
General public	1	15	50	50
Comforter or carer: no dose limit, however the Health Protection Agency (HPA) (formerly the National Radiological Protection Board) recommends the dose should not exceed 25 mSv over a 5-year period or 5 mSv in a single exposure.